Technical Field
This invention relates to residential smoke alarm/detector systems. In particular, this invention relates to a device and method of use for providing direct current (“DC”) backup power through a dedicated wiring circuit to an interconnected system of smoke detection devices installed in a residential or commercial building.
State of the Art
A reliably functioning system of smoke detectors in a home or commercial building saves lives. In the U.S., many states require smoke alarms/detectors in both residential and commercial buildings, particularly in new construction. Current smoke alarm systems vary in the manner through which the individual detectors are interconnected and powered. Most commonly, smoke detectors are wired into an isolated AC power circuit (“dedicated circuit”) in a residential or commercial building to provide a reliable, continuous source of power. In the event of a power failure, a conventional DC battery within each detector provides backup power to the device. This generally works fine, unless these backup-power batteries fail or are disconnected.
According to the National Fire Protection Association (“NFPA”), almost two-thirds of home fire deaths from 200-2009 resulted from fires in homes without smoke detector alarms or in homes where smoke detector alarms were non-functioning. The NFPA reports that eighty percent of smoke alarm failures during this period arose from a missing or disconnected battery, dead or discharged battery, or line alternating current (“AC”) power failure/shut-off/disconnect. When the voltage of a backup DC battery in an individual smoke detector weakens, a typical detector emits an audible alarm consisting of regular, loud beeps or chirps, alerting the building's occupant to replace the old, discharged battery with a fresh one.
This system of using replaceable batteries as backup power for individual smoke detectors, however, is flawed. A chirping smoke detector is widely perceived as a nuisance, particularly when the chirping begins at night when building occupants are sleeping. Smoke detectors are usually mounted on the ceiling, at best requiring a ladder or large stepstool to access the detector and change the battery. At worst, the detector may be mounted on a high ceiling, as much as thirty feet from the floor. Access to these ceiling-mounted smoke detectors is often troublesome and sometimes dangerous. The NFPA observes that “when smoke alarms should have operated but did not do so, it was usually because batteries are missing, disconnected or dead. People are most likely to remove or disconnect batteries because of nuisance activations. Sometimes, the chirping to warn of a low battery is interpreted as a nuisance alarm.”
Accordingly, what is needed is a device that provides a backup power source to an existing interconnected system of smoke detectors in a residence or commercial building, and monitors the functionality of each individual device.